It appears to me you're using the reference wrong!
The reference depicts the underlying 3d shapes and volumes of a simplified head. What you should NOT do is look at it and make an outline. You should construct the head using those shapes such as spheres and cylinders, then we'll talk about edits!
Ideally, you'd be looking at a realistic head and mastering that before you touch cartoons.
It's not my place to tell you what to do, but that's probably the best path you could take as a budding artist. The thing is, the person who drew your reference understands form to an extent, he understands placing objects in a 3d space. You, on the other hand, seem to try and represent things symbolically on a 2d plane without understanding what you're symbolizing!
For example, you drew a horizontal line for a mouth. To correct that, you drew a silhouette of a generic albeit recognizable sign for lips. Had you experience with some form of realism you would have likely simplified it to include a shaded upper lip and a lighter (or the absence of a) lower lip, with a shaded portion below the lower lip to signify that yes, there is a lower lip and it's casting a shadow because the light source is from above. You can observe this in tocky's example. Forget there are lips! there are only forms which are subject to light and shadow. The manga style you seem to want to draw well requires more understanding of realism and less of actual manga
style. Cartoons are simplified realism. So if you learn the real thing first there is nothing stopping you from making the
stylized simplifications you want in order to convey a cleaner and faster representation of a human face.
For your artistic health I can't stress how important it is to understand the real world before you draw things in a cartoon style, but I don't want to come across as a big mean "arg, no animu". I've talked to a lot of people who are unsuccessful artists because they study the manga
style and try to duplicate it instead of learning realism and simplifying it with ease into manga. You don't memorize that 12536 + 252 = 12788. That is horribly inefficient and impractical. You need to think of the numbers as quantities. Once you grasp the number as a quantity, you can multiply them, add them, subtract them, in ANY situation. The same applies to learning how things actually are and then manipulating them with style filters. You can do Marvel, manga, chibi, whatever. (although many choose to make their own stylized interpretation) You see, it only gets you so far to learn "tricks" such as a carrot nose or a dark triangle under an M for the mouth. That won't get you far at all. However, if in your mind you see a real person and then simplify it into the desired style you will have no limits and your capabilities as a character artist will be unhindered.
I really hope you learned something from this post. You can't pixel until you learn to draw.
